Non-volatile random access memory units (NVRAM) are used to store data permanently. Although non-volatile memory units maintain the memory content even without a supply of current, the memory content nevertheless dissipates sooner or later depending on its type (flash memory, magnetoresistive random access memory (MRAM), phase change memory (PCM), resistive random access memory (RRAM) or ferroelectric random access memory (FRAM)). Even non-volatile memory units must therefore be refreshed every once in a while.
In non-volatile memory units, so-called refreshes of the memory content stored therein are performed at certain time intervals in order to maintain the memory content. For this purpose, the memory content of the memory area is read in and the corresponding memory area is again overwritten with this read-in memory content.
A use of such non-volatile memory units in embedded systems, for example in a motor vehicle, proves to be problematic especially due to these refreshes.
A loss of the memory contents can result in a failure of the entire embedded system, which represents a high safety risk. For example, a sudden failure of an embedded system of a motor vehicle, for example of an engine control unit, represents a danger for occupants of the motor vehicle and other road users. Such a sudden failure can result in a driver of the motor vehicle losing control of the vehicle.
It is therefore desirable to prevent a loss of memory contents or indeed a failure of the embedded system.